Physical simulation is an important means of simulating the development of oil and gas reservoirs. It is indicated through practices that the larger the mold geometry, the closer the experimental results are to the actual mine field. Experimental cores are divided into natural and artificial ones. Natural cores are hardly obtained and relatively high in cost. So, artificial cores are commonly used to perform large-scale physical simulation. A sand-packed mold fails to simulate a fracture-pore type reservoir owing to low working pressure. Epoxy resin and aluminum phosphate are generally selected as existing cemented mold binders, but most of them require high-temperature sintering. In order to simulate a reservoir development process better, it is necessary for the artificial core to keep original oil-water saturation of the reservoir. With respect to a fractured core, the steps of creating fractures first and establishing saturation subsequently are generally used. Because fluids flow turbulently according to the fractures when saturated, the original water saturation cannot be established. There are two main methods for creating fractures in a large artificial core. In the first method, a metal sheet is inserted prior to the formation of the core and then pulled out to form fractures, but the occasion to pull the metal sheet out is hardly grasped. In the second method, a specific material is placed in a mold in advance, and then melted, dissolved and volatized by means of physical means, but residues will appear and the process is cumbersome.
In order to simulate the reservoir development process better, a physical mold needs to be similar to an actual reservoir, that is, the original oil-water saturation of the reservoir needs to be maintained. Methods for establishing the saturation include a drying method, a centrifugation method, and a displacement method. Both the drying method and the centrifugation method lead to the problem of uneven distribution of water in the core. The displacement method mainly refers to evacuating the core, filling water till saturated, and displacing the water with a reservoir fluid to establish the oil-water saturation. Due to the presence of fractures in the fractured core, the water saturation is often higher than a desired value, such that the desired oil-water saturation cannot be established.